Resurrecting this old thread, I have finally tracked down the source of "ghost notes" in my setup to my Virus Ti 2 Keyboard.
I recently added a Cirklon as the heart of my studio. It acts as the master MIDI router and clock, and all other devices sync to it, with all keyboards set to "Local off". This works great, as I can select a track on the Cirklon, and play the instrument that's assigned to that track from any connected keyboard or controller.
When I leave my gear turned on but inactive - i.e. I'm away from the gear doing something else - I've come back several times to find sustained ghost notes playing on whatever instrument is currently selected. Through a process of elimination I've finally identified the Virus as the culprit. Pressing the panic buttons on the Virus clears the problem.
For what it's worth, I upgraded to the latest OS on Saturday, so that hasn't fixed this bug.
Cheers,
Malcolm.